Caliciviridae, Filoviridae, Togaviridae Flashcards by Queenie Mae

Structure: Small (___), rounded, nonenveloped, single- stranded, positive RNA viruses.
* Cause ___ in humans.
* Previously recognized as major animal pathogens with a broad host range.
* ____ classified in the family of this in the 1990s.
*___ include__ and __ genera.
* Genogroups: ___ anad ___

CALICIVIRIDAE
-30-38 nm
- acute gastroenteritis
- Noroviruses (formerly Norwalk-like viruses)
- Human caliciviruses (HuCVs)
- Norovirus and Sapovirus
- Norovirus (I, II, IV) and Sapovirus (I, II, IV, V)

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Approximately 685 million cases of gastroenteritis caused by __ annually.
* About 200 million cases occur in children under 5, leading to 50,000 to 70,000 deaths yearly, mostly in developing countries.
* Major public health concern in both low- and high-income countries.
* MOT: Rapid spread due to ___, low infectious
dose (____), and high environmental stability.
* Easily transmitted via food, water, person-to-person contact, and airborne droplets.
* Virus persists in water despite treatment processes

CALICIVIRIDAE
Norovirus
fecal-oral transmission
<100 virus particles

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Moderate to severe gastroenteritis: ___,___,___,__ anad ___
* Symptoms typically appear __ post-infection and last ___.
* Vomiting more common in children than adults.
* ____ causes mild to moderate gastroenteritis, more prevalent in infants and toddlers

CALICIVIRIDAE
nausea, abdominal cramps, vomiting, watery diarrhea
- 1-2 days
- 1-3 days
- Sapovirus

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Maximum shedding occurs at symptom onset; can continue for 2- 3 weeks after symptoms resolve.
Infection does not confer long-lasting immunity, complicating control of transmission

Viral Shedding

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Diagnosis of CALICIVIRIDAE
* Culture in __
* __ is the most widely used identification method.
* Commercial __ kits available but have lower sensitivity and specificity than RT-PCR.
* Multiplex NAATs (e.g., ___ and ___) can detect Noroviruses and Sapoviruses from __ samples.

Human Intestinal Enteroids (HEI)
-RT-PCR
- ELISA
- Verigene Enteric Pathogens Test, FilmArray gastrointestinal pane
- stool

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Enveloped, complex, pleomorphic rodlike shaped capsid, negative sense SSRNA
* __ and __ - classified as members of the
family ___ but are now classified as___
* Long threadlike viruses, hence the name (____) -
range in size from ____.
* Cause severe or fatal hemorrhagic fevers and are endemic in Africa

FILOVIRIDAE
- Marburg and Ebola viruses
- Rhabdoviridae
- Filoviruses (Filoviridae)
- filum means thread
- 80 to 800–1000 nm

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MOT: Direct contact with bodily fluids, infected animals (__,__ and ___), fomites, sexual transmission
* Incubation period: __
* Fever, severe headache, muscle pain, weakness, gastrointestinal symptoms, hemorrhagic symptoms (bleeding from the eyes, ears, nose, and mouth, as well as internal bleeding) ultimately leading to multi-organ failure and death

FILOVIRIDAE
- fruit bats, monkeys, apes
- 2-21 days

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Named after the Ebola river
1979 Ebola re-emerged in __, with serial person-to-person spread
Another epidemic occurred in ____, in __.

Ebola Virus
- Sudan
- Kikwit, Zaire 1995

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Ebola virus Strains

Zaire ebolavirus
Sudan ebolavirus
Tai Forest ebolavirus
Bundibugyo ebolavirus:
Reston ebolavirus

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The most lethal strain, responsible for the majority of
outbreaks, with a mortality rate ranging from 50% to 90%

Zaire ebolavirus:

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: Associated with outbreaks in Sudan and Uganda,
with a mortality rate of about 40% to 60%

Sudan ebolavirus

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: A rare strain with a lower mortality rate,
associated with a single case

Tai Forest ebolavirus

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: Identified in Uganda, with a mortality rate of
approximately 25% to 50%.

Bundibugyo ebolavirus

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: Primarily found in animals, particularly in the
Philippines, and is not known to cause disease in humans

Reston ebolavirus

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Ebola Virus Pathogenesis

Filovirus Replication
Cytokine Storm
Tissue Damage

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: immune cells such as monocytes,
macrophages, and dendritic cells

Filovirus Replication

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production of high levels of proinflammatory
cytokines, similar to what occurs with superantigens

Cytokine Storm:

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necrosis in the liver, spleen, lymph nodes, and
lungs

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Tissue Damage:

The virus was first identified in ___ during simultaneous outbreaks in__,__,____,___ and ___
linked to laboratory workers exposed to infected ____

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Marburg Virus
- 1967
- Marburg and Frankfurt, Germany, and in Belgrade, Serbia
- African green monkeys

Marburg Virus Strains

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Marburg Virus (Marburg, Germany)
Ravn Virus

: The original strain,
associated with the first outbreaks.

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Marburg Virus (Marburg, Germany)

: Identified in a 1987 outbreak in the Democratic
Republic of the Congo, it is closely related to the Marburg virus.

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Ravn Virus

Diagnosis of FILOVIRIDAE
* __ A primary method for identifying the viruses.
* __ Available in some research settings.
* __: Conducted in BSL-4 laboratories.
* ____: Used to detect IgM and IgG antibodies
against the Ebola virus.

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RT-PCR Testing:
Electron Microscopy
Cell Culture
Antigen-Capture ELISA

Treatment/Prevention of FILOVIRIDAE
* Supportive Care:__,___,__ ___

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Fluid replacement therapy, kidney dialysis,
blood transfusions, favipiravir

Treatment/Prevention of FILOVIRIDAE Monoclonal Antibodies: ___ aand __

Treatments like ZMapp and MIL 77 are

Utilizing blood or plasma from recovered patients to provide immune support.

Convalescent Plasma Therapy:

Vaccines of FILOVIRIDAE: At least 15 Ebola vaccines are in development, with____ emerging as the first to complete Phase III clinical trials, showing substantial protection against EVD.

rVSV-ZEBOV

Major genera : __,___ and ___ * ___is the only member of the rubivirus group; disease manifestation: __ and its means of spread differ from those of the alphaviruses * Spherical enveloped viruses with a diameter of ___ genome is single stranded RNA * From ‘toga’, meaning the ___, and refers to the viral envelope

TOGAVIRIDAE -- Alphavirus, Rubivirus, and Arterivirus - Rubella virus -German measles - 50–70 nm - roman mantle or cloak

__ genus consists of about 32 viruses of which at least 13 are known to infect humans. ✓All of them are mosquito borne

Alphavirus

___, which is not arthropod borne and which causes rubella

Rubivirus

* No known ___ cause disease in humans

Arteriviruses

Alphavirus

A. Encephalitis viruses 1. Eastern equine encephalitis (EEE) 2. Western equine encephalitis (WEE) 3. Venezuelan equine encephalitis (VEE) B. Viruses causing febrile illness 1. Chikungunya virus (CHIKV) 2. O’nyong-nyong virus (ONNV) 3. Semliki Forest virus 4. Sindbis virus 5. Ross river virus

* Three members: __,__ and ___ cause encephalitis in horses and humans * Vectors:__ and __ * Reservoir: ____ * Vaccine: ___ have been developed for EEE and WEE and a ___ for VEE

Alphavirus—Encephalitis viruses - Eastern, Western and Venezuelan equine encephalitis viruses - Culex and Anopheles mosquitoes - wild birds - Formalinized vaccines - live attenuated vaccine

* In ___, means ‘that which bends up’, and refers to the posture assumed by patients suffering from severe joint pains * Incubation period is __ with an average of ____ * Vector is ___. * No animal reservoir has been identified

Chikungunya Virus - Swahili -1–12 days - 2–3 days - Aedes aegypti

Confined to Africa, is closely related to the chikungunya virus antigenically and causes a similar disease. * Transmitted by the anopheles species __ and ___ * ___causes a similar disease in the west India and South America

O’nyong-nyong Virus - (Anopheles funestus and Anopheles gambiae) - Mayaro virus

* Has not been associated with clinical illness in humans though neutralizing antibodies to the virus have been demonstrated in Africans

Semliki Forest Virus

* Originally’ isolated from __ in the Sindbis district of Egypt in 1952, has subsequently been recovered from other parts of Africa, India, Philippines and Australia. * In Africa, it is known to be associated with febrile illness in human beings

Sindbis Virus - culex mosquitoes

* Has been associated with epidemic polyarthritis in Australia

Ross River Virus

"____" * highly contagious virus that primarily affects humans and is transmitted through respiratory droplets when an infected person coughs or sneezes. * can also be transmitted from mother to fetus during pregnancy * Incubation period: ___ * Common symptoms include Mild fever, rash that starts on the face and spreads to the rest of the body, ___ (swollen lymph nodes), joint pain (more common in adults), cold-like symptoms (e.g., runny nose, sore throat)

Rubivirus—Rubella Virus “German Measles” - 14-21 days - lymphadenopathy

Infection during the first trimester poses significant risks to the developing fetus, potentially leading to___ * CRS can result in serious birth defects, including: 1 2 3 4 5 * The risk of it is highest when the mother is infected during the first trimester.

Rubivirus—Rubella Virus - congenital rubella syndrome (CRS) -* Heart defects (e.g., patent ductus arteriosus) * Hearing loss * Cataracts * Microcephaly * Developmental delays

* Diagnosis is primarily based on clinical presentation, including characteristic rash and associated symptoms * Serological tests can detect specific IgM and IgG antibodies against rubella virus. * ____can be used to detect viral RNA in clinical specimens.

Rubivirus—Rubella Virus -PCR (polymerase chain reaction) tests

Vaccination: * The most effective way to prevent rubella and its complications is through vaccination. * The ___ vaccine is commonly administered in childhood, typically around __ with a booster dose given between ___

MMR (measles, mumps, rubella) -12-15 months of age - 4-6 years

Caliciviridae, Filoviridae, Togaviridae Flashcards

(43 cards)